Combination Frequencies of the Infra-Red Bands of Quartz

Many observers have studied the infra-red absorption bands of quartz and have found regions of intense absorption at 9{μ}, 12.5{μ}, 20{μ} and 26{μ}. These regions of absorption are assumed to be the fundamental frequencies of quartz. By combining these assumed fundamental frequencies six bands in the region from 3{μ} to 9{μ} are accounted for. Also the writer has experimentally located two bands at 2.72{μ} and 3.18{μ} which have not been previously observed. The frequencies of these two bands agree with two combinations of the fundamental frequencies. This gives a total of eleven absorption bands for the ordinary ray of quartz, extending from 2.72{μ} to 26{μ} whose frequencies agree, with only small differences, with the calculated values.